Adding a review widget to the chat and activity tab when the trade is completed

[sergdeus]

A message that says something like “It looks like you haven’t left a review for this user yet. Tap here to leave a review!” when the trade is completed
Or at least “Trade completed. Tap here to leave a review!” although that could get redundant if you have already left that user a review before
Or maybe “You've already left this user a review. Would you like to update your review now?”